View source for 3qsk


==5 Histidine Variant of the anti-RNase A VHH in Complex with RNAse A==
<StructureSection load='3qsk' size='340' side='right'caption='[[3qsk]], [[Resolution|resolution]] 1.75&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3qsk]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus] and [https://en.wikipedia.org/wiki/Camelus_dromedarius Camelus dromedarius]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3QSK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3QSK FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.75&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3qsk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qsk OCA], [https://pdbe.org/3qsk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3qsk RCSB], [https://www.ebi.ac.uk/pdbsum/3qsk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3qsk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RNAS1_BOVIN RNAS1_BOVIN] Endonuclease that catalyzes the cleavage of RNA on the 3' side of pyrimidine nucleotides. Acts on single stranded and double stranded RNA.<ref>PMID:7479688</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
There is growing interest in the development of protein switches, which are proteins whose function, such as binding a target molecule, can be modulated through environmental triggers. Efforts to engineer highly pH sensitive protein-protein interactions typically rely on the rational introduction of ionizable groups in the protein interface. Such experiments are typically time intensive and often sacrifice the protein's affinity at the permissive pH. The underlying thermodynamics of proton-linkage dictate that the presence of multiple ionizable groups, which undergo a pK(a) change on protein binding, are necessary to result in highly pH-dependent binding. To test this hypothesis, a novel combinatorial histidine library was developed where every possible combination of histidine and wild-type residue is sampled throughout the interface of a model anti-RNase A single domain VHH antibody. Antibodies were coselected for high-affinity binding and pH-sensitivity using an in vitro, dual-function selection strategy. The resulting antibodies retained near wild-type affinity yet became highly sensitive to small decreases in pH, drastically decreasing their binding affinity, due to the incorporation of multiple histidine groups. Several trends were observed, such as histidine "hot-spots," which will help enhance the development of pH switch proteins as well as increase our understanding of the role of ionizable residues in protein interfaces. Overall, the combinatorial approach is rapid, general, and robust and should be capable of producing highly pH-sensitive protein affinity reagents for a number of different applications.

A combinatorial histidine scanning library approach to engineer highly pH-dependent protein switches.,Murtaugh ML, Fanning SW, Sharma TM, Terry AM, Horn JR Protein Sci. 2011 Jul 15. doi: 10.1002/pro.696. PMID:21766385<ref>PMID:21766385</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3qsk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Antibody 3D structures|Antibody 3D structures]]
*[[Ribonuclease 3D structures|Ribonuclease 3D structures]]
*[[3D structures of non-human antibody|3D structures of non-human antibody]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Camelus dromedarius]]
[[Category: Large Structures]]
[[Category: Fanning SW]]
[[Category: Horn JR]]
[[Category: Murtaugh ML]]
[[Category: Sharma TM]]
[[Category: Terry AM]]